The present invention pertains to the production of open cell grids in a highly advantageous and inexpensive manner, and pertains to the use of fiber to produce such grids The fibers can be cellulose or other sorts, such as various plastics, fiberglass, and the like. An important advantage of the invention is to utilize wood and non-wood fiber which is otherwise not utilized.
Trees raised in the United States of America for commercial purposes are of two general types, hard and soft. Softwoods are fully utilized for the manufacture of paper, newsprint, and other paper products. The large, good quality, hardwood trees are well utilized to produce lumber.
However, there are also hardwood trees which are relatively small, somewhat deformed, or not well suited for the production of lumber for various other reasons. Further, the smaller limbs of trees are not utilizable for lumber The present invention, so far as it utilizes wood fiber, is an advantageous way of utilizing this forest fiber resource which is otherwise wasted, or, at best, under utilized.
The invention can be accommodated to use with plastic fibers, such as polyethylene and polypropylene, as well as fiberglass, and more "exotic" man-made fibers, such as aramid. These additional fibers, depending upon the end use, will add strength, water resistance, and other desirable characteristics to the final open cell grids produced in accordance with the invention.
The invention has another important advantage in that it can utilize, in addition to low-grade trees, limbs and the like, as discussed above, waste fibers of all sorts. There is a tremendous problem in the world today of having to deal with disposition of waste material. Land fills are becoming filled, and the burden on the prime natural resources is increasing. By recycling waste materials, the pressure on the landfills, the air pollution, and the like are reduced, and at the same time trees are saved, thus well husbanding our forest resources.
The invention can work with waste paper of all sorts, including computer paper, magazines, newsprint, boxes, and the like, and it can even work with mixed fibers including both such cellulosic and non-cellulosic (man-made) fibers. This in and of itself is an important advantage, because waste paper from offices and residential communities contain many contaminants such as clay, ink, plastics, staples, and the like. This mixed waste paper, etc. can be used without prepatory processing such as deinking, bleaching, or the like, and with minimal prepatory processing, such as screening to remove some of the larger contaminants, to form a structural product in accordance with the invention. This so particularly if the grid is to be incorporated into the interior of another structural item, e.g. a door. This is very important with respect to recycling in that such mixed waste paper and waste materials, an unwanted and under-utilized fiber resource, can be used. Thus, the invention has the important advantage of the ability to recycle and incorporate all sorts of wood fiber, nonwood fiber, and nonwood waste without the added expense of separation of these materials to produce new lightweight but strong structural products and components of such products.
This invention utilizes some of the technology of U.S. Pat. No. 4,702,870 by the present inventor together with another. That patent is owned in common with the present invention.
The present invention produces grids of a monolithic one-piece character. The grids are formed in accordance with the invention either in final form or in near final form and therefore do not require any additional assembly and/or attendant handling The common prior art method of making somewhat similar structural honeycomb material begins from flat sheets or strips of paper or paper-like material which are glued at spaced points, pressed, and then expanded to produce a grid of diamond-like open cells. The present invention is substantially different from and is thought to be a substantial improvement over that prior art, in that no gluing at spaced points and no expanding processes are required. The present invention also provides a step forward in the art in that very complex structures (See FIG. 2E for example) can be produced. It is impossible to produce such complex structures with prior art methods because only uniformity of the cells throughout such prior art structures is possible.
The present invention also is to be distinguished from various kinds of other fiberboard and paper making devices and methods. An important characteristic of the invention is the use of a mold element which deforms during the molding process in order to compress the fibrous material in directions perpendicular to the direction of pressing, as well as parallel to the direction of pressing. This is not found in many other such techniques, including the manufacture of egg cartons, corrugated cardboard, and the like.
Several forms of the invention produce material continuously This is a substantial improvement over all of the prior art that is of a batch nature.